Mechanical pencil and method for making the same



March 24, 1942. JQCHIM I 2,277,109

MECHANICAL PENCIL AND A METHOD FOR MAKING THE SAME Filed July 10, 1941 V INVENTOR. 7&1}, WzQfiner Jocfidnv -4 I Patented Mar. 24, N42

MECHANICAL PENCIL AND METHOD FOR MAKING THE SAME Helmer R. Jochlm, Chicago, Ill., assignor to Rite- Rite Mfg. 00., i'ihicago, BIL, a corporation of Ellinois 2 Claims.

This invention relates to an improvement in mechanical pencils and to a method for making the same, and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

Theimprovement is designed especially for a mechanical pencil adapted for use by draftsmen who employ the pencils in drawing along the edges of T-squares, triangles, curves and the like. Such a pencil is shown in a patent to H. F. Smenner, No. 2,170,734, granted August 22, 1939. Said pencil is capable of using leads of a very small diameter, as for example, 1 ss than of an inch, and has a tip terminating in a long, slender, almost cylindrical section whose free end has an external diameter but little greater than that of the lead. It may be used to draw a line along the edge of a T-square, triangle, curve or other edge without varying the uniformity of the distance of the pencil point from saidedge.

Great difiiculty has been encountered in providing the tip of such pencil with the integral,

. comparatively long, thin walled, substantially cythe connection between the main body of the tip and the small diametered sleeve which encloses thelead in the neighborhood of its exposed point.

In the drawing- Figure l is a view representing a side elevation of a mechanical pencil containing the invention.

Figure 2 is a view partly in section and partly in elevation showing a blank for the main part of the tip.

Figure 3 is a perspective view of an elongated tube or sleeve of stainless steel.

Figure 4 is a View similar to Figure 2, with said stainless steel, tube which is to constitute the elongated tip of very small diameter inserted into the main partof the tip.

in Figure 4), and is ofsuch thickness that its inner cylindrical surface will be in substantial alignment with and constitute a continuation of the bore l2 of the tip. .Its inner diameter is greater than it is designed to be in the finished structure.

A mandrel of approximately the diameter of the lead to be used in the pencil isthen, inserted into the tube It, and the end ll which appears as an abrupt shoulder in Figure 4 is swaged down upon the tube Hi which itself is swaged and polished upon the mandrel to reduce it to the required diameter as shown in Figure 5 at H, the swaging action resulting in the formation of an annular shoulder W on the stainless steel tune It and of a gradually thinning out and overlapping of the brass shoulder I l upon the annular shoulder M as at li This produces a onepiece efiect and at the same time an eficient lock between the brass tip H and the stainless steel tube or sleeve id When inserting the tube It into the counterbore l3, it may be preferred to file the end to be inserted to produce a slight taper, as shown at ii in Figure 4.

I claim as my invention:

1. In a. mechanical pencil, a tapered metal tip provided with a bore and with a counter-bore of greater diameter at its end, a steel sleeveof the diameter of said counter-bore fixed therein with a substantial part of its length projecting beyond said tip, said tube and the end of said tip being swaged down the one upon the other to form a shoulder on said tube overlapped by the metal of said tip to interlock the tube and tip together and to reduce the tube projecting beyond the tip to a predetermined small interior diameter.

' Figure 5 is a view partly in. section and partly in elevation showing the finished tip.

Referring now to the drawing, 80 indicates a pencil body to which is secured in any familiar manner a tapered tip I I preferably made of brass. Said tip is provided with the usual bore E2 to 7 receive the lead. It is also counter-bored from may be driven into the counter-bore 13 (as shown.

2. A method of making a tapered metal tip with a thin steel sleeve of comparatively small diameter projecting beyond said tip, which consists in providing a comparatively heavy tapered brasstip with a central bore; in forming adjacent the end of said tapered tip a counter-bore of greater diameter than said first named bore and concentric therewith; in driving a thin metal sleeve of the outer diameter of said counter-bore into said counter-bore; and in then swaglng the end of said brass tip and said steel tube down upon a mandrel to thin out said tube and reduce it to a predetermined small diameter in manner to form an annular rounded shoulder in said steel are made to simulate an integral structure of tip and sleeve.

. HELMER R; 'JOCHIM. 

